Process and apparatus for injecting liquid fuel



Nov. 16, 1965 G. CREMER ETAL. 3,217,780

PROCESS AND APPARATUS FOR INJEGTING LIQUID FUEL Filed March 7, 1962 MEANS TO OPEN AND CLOSE THE SUPPLY INLETS United States Patent PROCESS AND APPARATUS FOR INJECTIN G LIQUID FUEL Gottfried Cremer and Heinz Behrens, Cologne-Junkersdorf, and Walter Storheck, Frechen, near Cologne, Germany, assignors to Fetok G.m.b.H., Chur, Switzerland, a company of Switzerland Filed Mar. 7, 1962, Ser. No. 178,177 Claims priority, application Germany, May 3, 1961, 6 Claims. (Cl. 158-77) A 37,342

This invention relates to -a process for the heating of furnaces, especially but not essentially in the ceramics industry, by means of a liquid fuel such as oil injected under pressure, using a multi-jet injection nozzle. The expression multi-jet nozzle connotes that the nozzle is effective to produce two or more types of jets.

The use of multi-jet injection nozzles is already known, the intention being to obtain an even distribution of the fire in the firing channel and hence even firing of the ceramic articles. In one known nozzle, the injection channels of the nozzle are arranged at an angle to one another in the same plane or in different planes, and the nozzle may also be displaced round a vertical axis.

By this invention, an attempt is made to use another heating principle and moreover successfully, in that the character of the flame can be altered during the course of the operation.

In the case of tunnel kilns with oil burners fitted later-ally, there is, for example, generally the difiiculty of attaining an even distribution of the temperature over the width of the furnace. If such a furnace is fired with a burner which injects an almost unatomized jet into the combustion space, then it is found that the jet, which burns along its injection path, lead-s to too high a temperature at the end of the injection path. If, on the other hand, the nozzle works with a completely atomized jet, the temperature near the burner nozzle is appreciably higher than, for example, in the middle of the burner carriage traversing the tunnel kiln.

An object of the invention is to facilitate equalisation of the temperature distribution over the whole of the cross-section of the furnace, and, at the same time, to permit adaptation of the firing to the circumstances prevailing at any given time. The suggestion has recently been made that the furnace should be heated with atomized oil during the heatingup period, and subsequently with oil which is injected largely unatomized. This process has proved satisfactory, but only represents an exceptional case, which it is the object of the present invention to generalise.

The process according to this invention is characterised by the fact that the oil is injected in partly finely atomized and partly practically unatomized. The oil may be injected finely atomized and practically unatomized alternately. It is possible, however, for the injection of the oil to be effected simultaneously in the finely atomized and in the practically unatomized state, the oil being, for convenience, injected by a number of jets concentric to one another, and is either atomized or unatomized as the case may be.

In the process according to the invention, the oil can be fed continuously to the nozzle under even pressure, or can be fed to the nozzle intermittently.

A device for carrying out the process according to the invention may comprise a hollow tube with a nozzle of essentially conventional type of which the nozzle aperture may be closed by means of a needle, this needle, in accordance with the present invention, having a bore hole connected to a branched feed pipe for the liquid fuel, with a free outlet at the end of the nozzle.

It is particularly convenient if the needle is placed under spring pressure in the direction of the nozzle aperture, and provides a closure device for each of the two feed pipes.

Other parts of the invention are embodied in the preferred forms which will now be described in some detail with reference to the accompanying drawings in which:

FIG. l is a section of one form of device in one operational position;

FIG. 2 is a section similar to FIG. 1 with the device at another stage of the fuel feed; and

FIG. 3 is a diagram of an arrangement providing immediate feed of the liquid fuel through two feeder devices.

In the case of the injection nozzle shown in FIG. 1, in the hollow tube 1 which has a nozzle aperture 5 there is provided a nozzle duct or needle 2, which is pressed against the nozzle aperture 5 by the spring 4 acting upon the guide collar 3. The spring 4 rests against the rear wall 6 of the hollow tube 1. In the dividing partition 7 is fitted a sleeve 8 which guides the nozzle needle 2.

As a result of the dividing partition 7, two hollow spaces -9, 10 are formed which are connected through pipes 11, 12 with a common feed pipe 13 for the liquid fuel. In the pipes 11 and 12 there are provided closure devices 14. and 15. In addition, the needle 2 is provided with a bore 16.

With the closure valves or closure devices 14, 15 in the position shown in FIG. 1, the hollow space 10 is connected to the fuel feed pipe 13. From this space 10, the oil passes through the bore 16 into the end of the nozzle needle 2 adjacent the nozzle aperture 5, where it is ejected practically unatomized into the combustion space. The oil feed may of course be effected continuously or intermittently, according to the type of heating desired.

In the position shown in FIG. 2, the other extreme case has been reached, that is the closure-device 14 has been opened and the closure device 15 is closed. The fuel thus arrives immediately in the space 9. Since the needle duct 2 has two different cross-sections a and b, the needle is pushed backwards in the direction of the arrow 0 against the force on the spring 4, and the fuel leaves the partially open nozzle aperture 5 as a finely atomized cone of fuel. In this instance, too, the fuel can be fed continuously or intermittently. Furthermore by suitable choice of the size of the needle duct 2 and the force of the spring 4, it can be arranged for the needle duct 2 to enter a state of oscillation so that, even with continuous feeding of the fuel, the pressure of which is cyclically varying, a constant vibration of the needle and therefore a constant alteration in the nozzle aperture 5 is attained.

In the constructional example shown in FIGS. 1 and 2 either atomized fuel or unatomized fuel can be injected alternatively by opening either the closure device 14 or the closure device 15. Also, both closure devices can be opened more or less Widely, thereby obtaining an overlapping of 'both types of fuel feed.

A further modified form of construction of the principle on which this invention is based is shown in FIG. 3. In this constructional form, the two closure devices 14 and 15 are omitted. Instead, pumps 19 and 20 are supplied on the two branch pipes 17 and 18 for charging the two hollow spaces which are not shown in this drawing. In this case it is possible either to inject in the atomized state, in which event the pump 19 is set in motion, or else the fuel is injected more or less unatomized, working only with the pump 20. On the other hand, it is possible to run both pumps 19 and 20 together, when an overlapping of the two methods of injection will be obtained.

The pumps 19 and 20, which are shown as singlecylinder piston pumps, are naturally only shown by way of example. It would be possible to use multi-cylinder piston pumps or other types of pumps, for example, geared pumps. If it is only desired to inject comparatively small quantities of fuel per hour, then it is preferable to work with intermittent injection, in which case the use of a single-cylinder piston pump is to be recommended.

If the fuel is injected intermittently, it is possible to arrange in many instances for the two pumps to be synchronised in such a manner that the atomizing and the non-atomizing injection follow one another at specified intervals of time. In this event, however, it is a particularly simple and convenient method of working if, instead of using two separate single-cylinder piston pumps, a multi-cylinder piston pump is employed, where the crank angles of the two cylinders are suitably chosen in relation to one another. It is then possible, for example to inject atomized and non-atomized fuel alternately, or to work with a simultaneous injection of both atomized and nonatomized fuel. Clearly, any intermediate position can then be selected.

It will be apparent to those skilled in the art that by injecting a solid stream of liquid fuel and a spray of liquid fuel into the associated furnace, the furnace is heated in a more uniform manner than by the conventional systems.

We claim:

1. A method of heating a furnace by means of a hollow body closed at one end and having an orifice at the other end opening into the furnace; a transverse partition dividing the body into two compartments; an elongate reciprocable element having an axial bore, said element traversing one of the compartments and extending through the partition into the other compartment and adapted to produce a jet stream by liquid fuel passing therethrough, said element having a spray inducing means at one end thereof; and a valve structure movable between two positions for the cyclic admission of liquid fuel to the compartments of the body, comprising:

the step of passing a stream of liquid through the element to produce a jet of fuel from the body into the furnace;

the step of passing a stream of liquid fuel to the spray inducing means of said element to produce a spray of fuel through the orifice of the body into the furnace; and

the step of cyclically varying the pressure of the liquid fuel flowing in each of said streams.

2. Apparatus for injecting liquid fuel into a furnace for combustion therein comprising:

a hallow body closed at one end and having an orifice in the other end communicating with a furnace;

a transverse partition dividing said body into a first and a second compartment, said first compartment including the closed end of the body and the second compartment including the orifice;

means providing a hollow needle duct having a spray inducing means at one end thereof, said needle duct means traversing the first compartment of said body and extending through said partition into the second compartment of said body, said needle duct means being movable to bring the spray inducing means at one end thereof into and out of obturating rela- 5 tion with the orifice in the second compartment, said needle duct means having an enlarged extended surface portion on the end portion thereof adjacent the spray including means and disposed in the second compartment whereby when the enlarged extended surface portion is exposed to fluid pressure in the second compartment movement of said needle duct means is effected in a direction out of the second compartment;

means normally maintaining the end of said needle duct means in o'bturating relation with the orifice;

liquid fuel supply inlets communicating with each of said compartment; and

means to cyclically open and close said supply inlets,

said means to open and close constructed to open one inlet and close the other inlet whereby when liquid fuel is introduced into the second compartment said needle duct means is moved out of obtu rating relation with the orifice and the liquid fuel from the second compartment is caused to pass through the orifice to project a spray into a furnace, and when liquid fuel is introduced into the first compartment the liquid fuel is caused to pass through the needle duct means and thence through the orifice of said body to effect a jet stream into the furnace.

3. The apparatus defined in claim 2 wherein said means normally maintaining the one end of said needle duct means in obturating relation with the orifice consists of a spring.

4. The apparatus defined in claim 3 wherein said spring is disposed within said one compartment of said body.

5. The apparatus defined in claim 2 wherein said means to cyclically open and close said supply inlets includes a separate valve in each of said supply inlets, each of said valves movable between a fully open position and a fully closed position.

6. The apparatus defined in claim 2. wherein said means to open and close said supply inlets includes a pump connected to each of said supply inlets, respectively.

References Cited by the Examiner UNITED STATES PATENTS 423,012 3/1890 Wilson l581l7.5 1,737,945 12/11 929 Rigby 239 107 5 2,578,934 12/1951 Janssen 15873 0 3,076,607 2/1963 Cordier 15873X FOREIGN PATENTS 239,548 11/1909 Germany.

JAMES W. WESTHAVER, Primary Examiner.

MEYER PERLIN, Examiner. 

2. APPARATUS FOR INJECTING LIQUID FUEL INTO A FURNACE FOR COMBUSTION THEREIN COMPRISING: A HOLLOW BODY CLOSED AT ONE END AND HAVING AN ORIFICE IN THE OTHER END COMMUNICATING WITH A FURNACE; A TRANSVERSE PARTITION DIVIDING SAID BODY INTO A FIRST AND A SECOND COMPARTMENT, SAID FIRST COMPARTMENT INCLUDING THE CLOSED END OF THE BODY AND THE SECOND COMPARTMENT INCLUDING THE ORIFICE; MEANS PROVIDING A HOLLOW NEEDLE DUCT HAVING A SPRAY INDUCING MEANS AT ONE END THEREOF, SAID NEEDLE DUCT MEANS TRANSVERSING THE FIRST COMPARTMENT OF SAID BODY AND EXTENDING THROUGH SAID PARTITION INTO THE SECOND COMPARTMENT OF SAID BODY, SAID NEEDLE DUCT MEANS BEING MOVABLE TO BRING THE SPRAY INDUCING MEANS AT ONE END THEREOF INTO AND OUT OF OBTURATING RELATION WITH THE ORIFICE IN THE SECOND COMPARTMENT, SAID NEEDLE DUCT MEANS HAVING AN ENLARGED EXTENDED SURFACE PORTION ON THE END PORTION THEREOF ADJACENT THE SPRAY INCLUDING MEANS AND DISPOSED IN THE SECOND COMPARTMENT WHEREBY WHEN THE ENLARGED EXTENDED SURFACE PORTION IS EXPOSED TO FLUID PRESSURE IN THE 